Adolescence is a developmental period associated with a dramatic increase in risky behaviors including substance use and other potentially health-compromising behaviors. Extensive research has been conducted to identify the factors that may heighten the vulnerability for engagement in risk behaviors among adolescents. Among such factors, early adversity and its developmental effects across neural, socio-cognitive, and emotional domains has been often linked to heightened vulnerability for delinquent behaviors and risk taking. Although the relationship between psychosocial adversities and engagement in risk taking behavior has been well established, ethical and practical concerns have limited our ability to conduct experimental research that would allow a direct investigation of the causal role of psychosocial adversities on risk taking. As such, our knowledge about the nature of this relationship and the mechanisms underlying it remains limited. In line with the goals of this international collaboration application, the present study aims to address these limitations and assess the impact of early psychosocial adversities on adolescent risk taking, as well as to explore the mediating role of disinhibitory processes assessed through a behavioral measure. To this aim, we will use a unique sample of adolescents in Romania who, over the past 10 years, participated in a randomized clinical trial of a foster care/family intervention and who are now entering early adolescence. In this clinical trial, infants abandoned since birth and raised in institutions in Bucharest, Romania were randomly assigned either to be removed from the institution and placed into a family/foster care intervention or to be left in the institutions to care as usual. These children were subsequently followed through 8 years of age such that the sample has been well characterized with regard to multiple domains of psychosocial functioning. Given the uniqueness of the sample as well as the innovative assessment approach, the current study represents a unique opportunity to understand how early psychosocial deprivation may impact disinhibitory processes as risk taking vulnerability which may in turn heighten the likelihood of engagement in risky behaviors in adolescence. This is particularly relevant as prevention and intervention efforts move toward idiographic strategies that attempt to identify deficits and provide relevant skill development for such deficits. Thus, the ability to identify the processes underlying deficits and vulnerabilities is crucial for prevention and intervention development targeting those most at risk. PUBLIC HEALTH RELEVANCE: Empirical support for the impact of early adversity on risk-taking behavior among adolescents as well as for the mediating role of disinhibitory processes will accelerate our understanding of the risk factors that may be responsible for the dramatic increase in risky behaviors, including substance use and other potentially health- compromising behaviors, associated with this developmental period. Empirical evidence emerging from this study may guide prevention efforts targeting specific vulnerabilities associated with early adversity prior to the escalation of risky behaviors in later adolescence.